KOMUNALNA ENERGETIKA / POWER ENGINERING 2012
KOMUNALNA ENERGETIKA, _.
PROGRAMME 2012
KOMUNALNA ENERGETIKA / POWER ENGINERING, 0
Programme of the meeting
KOMUNALNA ENERGETIKA 2012, _.
KOMUNALNA ENERGETIKA / POWER ENGINERING, 000
KARG, L.
»SMART ENERGY MADE IN GERMANY: FIRST RESULTS OF THE E-ENERGY PROGRAMME«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 1
Affordable and reliable energy supply is essential for our industrial growth. In the course of the basic energy reform in Germany, the structure of the supply system will undergo far-reaching changes in the coming decades. For example, the number of small and decentralised producers with highly volatile, weather-dependent power generation will increase. These developments pose a great challenge for grid operators.
PAPIČ, I.
»SMART GRIDS DEVELOPMENT PROGRAM IN SLOVENIA«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 2
The concept of Smart Grids builds upon the modern concept of operation and power system planning. By joining classical (large centralized generation units, a transmission and distribution network) and new elements (distributed generation, advanced metering infrastructure, demand side management, virtual power plants, electric vehicles and energy storage systems), SmartGrids creates an effective system.
RENKO, J.
»LOCAL MICRO-INTEGRATED SUPPLY WITH ENERGY AND LIGHT«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 3
BENEŠ, I.
»DISTRIBUTED ENERGY AND SMART GRID CAN CONTRIBUTE TO SURVIVE DISASTER«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 4
The paper presents Czech research project in the field of smart critical infrastructure. Aim of this project is to create bridge between liberalized power business and new challenges rising from global risks. During the disaster it is necessary to ensure basic human needs and protection. The continuity of critical infrastructure must be secured against the consequences of cascading phenomena and the domino effect. Project solves the resilience of power distribution against national transmission grid blackout. Project’s goal is to demonstrate possibility of crisis demand side management that enables to provide necessary electricity for residents and critical infrastructure through adaptive distribution grid islanding. This function should be a basic functionality of smart grids. Project No2A-1TP1/065 „Increasing the resilience of the distribution system against long-term transmission grid blackout in order to enhance public safety” was supported by the Czech Ministry of Industry and Trade in the framework of “Sustainable prosperity” program. Project is called RESPO - REsilient POwer. This paper presents successful story of how society is willing to invest in resilience after a disaster experience.
ROPOŠA, S., ŠTUMBERGER, G.
»SMARTGRIDS IMPLEMENTATION IN THE CASE OF ELEKTRO MARIBOR«
KOMUNALNA ENERGETIKA / POWER ENGINERING, 5
Limited sources of fossil fuels and emissions of greenhouse gases related with the combustion of these fuels force use to increase the use of renewable energy sources. Unfortunately, the renewable energy sources are often distributed in the space and are not always available. Technical solutions for utilization of renewable energy sources are relatively expensive while the cost of energy, produced in this way, are too high to be economically bearable without national support schemes.
In spite of aforementioned drawbacks, European Union and Slovenia have made political decisions to support energy production from renewable energy sources. The electrical power generation based on renewable energy sources in Slovenia is focused on utilization of sun energy, water energy and biomass. A substantial increase in the number of installed electric power generation units, based on renewable energy sources, has been reported the last years. The share of photovoltaic power plants is dominant. It must be pointed out that the power system, as well as the transmission and distribution networks, were designed and build considering the energy flow from the power plants towards consumers. However, the increasing share of distributed electrical power generation units, connected to the electricity network, can change the direction and increase the dynamics of changes in the power flow. Such operation could cause problems in the electricity networks not designed for that kind of operation. The solution called SmartGrids should help to solve problems, related with the increased share of distributed power generation connected to the electricity networks.
VOVČKO, B., ŠTRICELJ, A.
DIFFERENT SOLAR MODULES - COMPARISON OF THE ENERGY YIELD AND PRACTICAL OPERATION EXPERIENCE
KOMUNALNA ENERGETIKA / POWER ENGINERING, 6
The purpose of this paper is to demonstrate practical experiences and results of operations of the various solar power technologies and implementations. In this paper we present a comparison of the energy yield of thin-film amorphous and monocrystalline solar modules, for the small solar power stations (MFE) of TE Brestanica at different orientations and small angles. In the first two chapters we present data for the solar power stations MFE TEB 1-3, in the third chapter we present a comparison of the energy yield of thin-film amorphous and monocrystalline solar modules based on the analysis of operation MFE TEB 1-3. In the last chapter we present a decision and proposals for the future investors, resulting from the preliminary findings.
SEME, S., ŠTUMBERGER, G.
EFFICIENCY OF SILICON SOLAR MODULES AT DIFFERENT CLIMATIC CONDITIONS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 7
This paper deals with the impact of different climatic conditions on the efficiency of silicon solar modules. The mono-crystalline, the poly-crystalline and the amorphous silicon solar modules are compared. According to the measurements of IU characteristic of the solar module and solar radiation, the efficiency of individual silicon solar modules has been determined. It is shown that the efficiency as a function of different climatic conditions for a silicon solar modules varies considerably. Slowly increasing efficiency characteristic as a function of intensity of solar radiation is shown in amorphous silicon solar modules, while the poly-crystalline and mono-crystalline silicon solar modules, this characteristic is flat.
DEŽELAK, K., DEŽAN, K., DEŽELAK, D., BELIČ, E., ŠTUMBERGER, G.
INTERNAL RATE OF RETURN FOR A SOLAR POWER PLANT IN CASE OF MOVABLE PHOTOVOLTAIC MODULS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 8
In proposed paper the internal rate of return for a solar power plant investment is mainly dealt. The main parts of the solar power plant are represented by the photovoltaic moduls, which could be static or movable. In case of movable photovoltaic moduls, where moduls are following to the movement of the sun, the amount of the produced energy could be even up to 30 % higher than in case of static photovoltaic moduls. On the other hand an investment in movable solar plant leads to the higher initial costs of the whole investment.
PIRC, A., DROBNIČ, B., MORI, M., SEKAVČNIK, M.
PLANNING OF A SELF-SUFFICIENT ENERGY SYSTEM WITH INTERNAL COMBUSTION ENGINE
KOMUNALNA ENERGETIKA / POWER ENGINERING, 9
The paper presents method of optimization of a self-sufficient energy system configuration. At the beginning an optimisation method for advanced planning of energy supply systems is presented. Secondly, Mathwork’s Simulink was used to describe dynamic mathematical model consisting of energy user, energy production unit (internal combustion engine - ICE), energy saving capacities (battery) and regulation. At the end optimal system was found through a series of simulations which ensures stable and rational energy supply with respect to different rules of operation, particular sub-system’s sizes and economical aspects. At the end, results, appropriate diagrams and future guidelines are shown.
HOSNAR, J.
ELECTRICITY PRODUCTION BY MICROTURBINE
KOMUNALNA ENERGETIKA / POWER ENGINERING, 10
The survey is based on the examination of the possible use of water power by building microturbines for electricity generation purposes. Water is one of the renewable sources, wich can it be potential (water drop and flow) for convertion in "green energy".
DEŽELAK, K., PIHLER, J., FLUHER, B., ŠTUMBERGER, G.
COMPARISON OF SMALL HYDRO POWER PLANTS: HYDRO MATRIX TURBINE VS. MOVING HYDRO POWER PLANT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 11
In proposed paper the comparison of two possible solutions for small hydro power plant construction is dealt. In that way the technical, as well as financial parts are observed. The first proposed solution is hydro power plant with the hydro matrix turbine, whilst the second solution is construction of so called moving hydro power plant. The choice of such solutions depends on particular water flow.
MÜHLBACHER, J.
POWER ENGINEERING AND ENVIRONMENTAL PROBLEMS IN CZECH REPUBLIC
KOMUNALNA ENERGETIKA / POWER ENGINERING, 12
The thesis deals with the environmental impacts of power energy generation in Czech Republic and the possibilities of land recultivation.
ČERNELIČ, J., ŠTUMBERGER, G.
LABORATORY PROTOTYPE OF A STATIC VAR COMPENSATOR
KOMUNALNA ENERGETIKA / POWER ENGINERING, 13
This paper presents a design of a laboratory prototype of a static var compensator. Compensator is made of a DC-link, two-stage three-phase inverter and passive LCL filter. For control, Voltage oriented control with PI regulators is used, along with space vector pulse-width modulation. Results of the experiment have shown appropriate design and good responses in transient conditions.
KOLENC, M., PAPIČ, I., BLAŽIČ, B.
LOCAL VOLTAGE CONTROL IN SMART GRIDS WITH TIME DEPENDENT POWER FACTOR
KOMUNALNA ENERGETIKA / POWER ENGINERING, 14
This paper deals with the influence of a lagre share of dispersed generation (DG) on a voltage profile in distribution networks. Until recently, the newly installed DG operated only with constant power factor, which was usually cos = 1. Countries around the world are now accepting the new rules and guidelines, which require that all DG participate in the voltage regulation, as they are the main reason for the voltage rise in distribution networks. Slovenia has already issued a document that prescribes different static characteristics Q(U), which determine the power factor of DG with respect to the voltage at the connection point.
As the new technologies nowadays allow bidirectional data flow in almost real time, more active participation of generators in voltage regulation is possible. Concept of voltage regulation which exploits these ideas is presented. At a certain intervals desired cos can be send to all generators in the network. Advantages of such a regulation are pinpointed out. Different solutions were evaluated by means of simulation on a real medium-voltage network, which demonstrate good flexibility when using such a methods.
HERMAN, L., PAPIČ, I.
OPTIMAL REACTIVE POWER CONTROL IN INDUSTRIAL NETWORKS WITH DISTORTED VOLTAGES AND CURRENTS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 15
In modern industrial processes, the number of nonlinear loads, which are known to be a major source of current harmonics, is constantly growing. At the same time, the number of reactive power compensators operating in these networks is also growing. Although compensators are not sources of harmonic distortions, they may cause high amplifications of harmonics by creating resonance conditions. This can cause malfunctions or even loss of equipment. Due to the growing number of reactive power compensators in a typical industrial network, the control of these networks is also becoming increasingly demanding. An industrial network operator has a difficult task of finding an optimal configuration of compensators, which covers reactive power demands and at the same time does not cause resonance amplifications of harmonics. Thus, in this paper, a concept of a virtual compensator is proposed. It combines all reactive power devices of a certain network within a single control scheme. This gives the operator the ability to control each compensator independently in real time and to achieve optimal configuration of compensators, for every operation point of the network. The effectiveness of the proposed algorithm is demonstrated on the realistic industrial network model by means of simulation.
KŘÍŽ, J., PISTORA, M., NOHÁČOVÁ, L., VELEBA, J.
POSSIBILITIES OF BLACK-START WITH USING RENEWABLE SOURCES ENERGY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 16
The risk of a large loss of power supply (blackout) cannot be entirely excluded. Therefore the power grid has to be prepared for power restoration. One possibility of power supply restoration after blackout is a black-start of one energy source and starting up self-consumption of a larger power station.
Due to rapid increase in renewable energy sources installed power, many new large-enough power plants have been built in recent years. These power plants would be sufficient to power-up self-consumption of a larger power plant.
This paper evaluates the possibility of starting self-consumption of coal power plant Ledvice using wind farm Kryštofovy Hamry.
GAŠPARINČIĆ, J., ŠTRICELJ, A.
DEVELOPMENT OF GAS TURBINES AND ELECTRO - ENERGETICAL SYSTEM TERTIARY CONTROL
KOMUNALNA ENERGETIKA / POWER ENGINERING, 17
Nowadays gas turbines have great significance in electro-energetics. In year 1905 the Brown Boveri company erected first commercial gas plant for production of electric energy. In all states in development gas plants are mostly used for covering system reserves.
At the greater disorders in electro – energetical system tertiary control has relevant role at the failure of larger blocks in system when it helps secondary control and together they remove incurred unbalance of active power. Therefore in electro – energetical system units that can cover tertiary control must be always available. Reserve of overall power must be activated in 15 minutes that can offer fast gas turbines, accumulated hydroelectric power plants and pumped storage power stations.
KUŠTRIN, I., SENEGAČNIK, A., JAMŠEK, M.
HARMFUL EFFECTS OF AIR LEAKAGE INTO PULVERISED-COAL FIRED BOILER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 18
The paper presents the reasons and consequences of uncontrolled air on the operation of steam boilers with dust firing i.e. combustion of coal crushed into powder. This type of combustion is more advanced than the combustion of solid fuels of larger granulation. It enables achieving higher output and efficiency. Several conditions must be fulfilled to enable quality combustion. One of these conditions is the optimum fuel to air ratio. This condition can be met if good control over the allocation of combustion air to the burner nozzles is possible. Usually it is possible to achieve from the perspective of installed measurement and control equipment but a major obstacle to this is an entry of uncontrolled air into the boiler. This makes it impossible to maintain optimum conditions for quality combustion.
KUŠTRIN, I., LENART, J., KOKOVNIK, A., GOSTINČAR, P., HOČEVAR, M.
COMBUSTION OPTIMIZATION WITH RESPECT TO COAL-DUST DISTRIBUTION BETWEEN BURNER NOZZLES
KOMUNALNA ENERGETIKA / POWER ENGINERING, 19
Any combustion should be optimized as much as possible to reduce specific fuel consumption and emissions of harmful substances to environment. Optimization of pulverized coal combustion is a complex task. Coal mills are also fans for pneumatic transport of coal particles to burners. Every mill supplies coal dust to two, three or four nozzles of the same burner. Due to large dimensions and complex geometry of mill and coal dust ducts and stochastic milling process it is practically impossible to evenly distribute coal dust between burner nozzles. It is easier to distribute combustion air according to actual coal distribution which is constantly changing. Coal distribution is affected by coal-feeder load, wear of main mill components and coal properties.
Paper deals with the method for continuous measurement of coal distribution in coal dust ducts after the mills. Electrostatic discharge sensors are applied.
MELE, J., SENEGAČNIK, A.
MINIMAL VELOCITY OF FULL FLUIDIZATION – A NEW DETERMINATION METHOD
KOMUNALNA ENERGETIKA / POWER ENGINERING, 20
The article introduces the method for characterization and control of fluidized beds with wide size distribution of particles. A laboratory unit has been made for the purposes of experimental research. Our goal is to make an automatic control protocol to find minimum necessary flow of fluidization fluid to run the process at full fluidization. On the basis of measured differential pressure and gas velocity, programme can find the optimal operation area. The method determines a single point among many points with almost same differential pressure and various gas velocities. This method can be used for controlling fully fluidized bed at minimum gas flows in CFB gasificators, fluidized bed furnaces, fluidized bed sanding machines, etc.
BELAK, L., MARUŠA, R., PIHLER, J., ZAGORIČNIK, A.
RECONSTRUCTION OF 220 KV BUS IN THE SUBSTATION 400/220/110 KV PODLOG
KOMUNALNA ENERGETIKA / POWER ENGINERING, 21
This Article describes the reconstruction of 220 kV bus (isolation and the corresponding material) in the substation 400/220/110 kV Podlog. The switching substation 220 kV has been in operation since the early seventies. Due to the long year operation and to the worn out equipment, the operations are no longer reliable. Because of this, the bus reconstruction was made in 2011. At that time, there was a primary objective that during the reconstruction the electro energetic system would be as less disturbed as possible. For this purpose, has been analyzed the operation of the 400 and 220 kV network during the reconstruction. The focus was on the implementation of the reconstruction to ensure the least disturbed electro energetic system and consequently the uninterrupted supply of electricity to consumers.
MARUŠA, R., VORŠIČ, J., PIHLER, J., ZUPAN, B., GRADNIK, T., BELAK, L., FERLIČ, R.
DETECTION OF COMBUSTIBLE GASES IN THE POWER TRANSFORMER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 22
The paper presents an upgrade of existing gas (Buchholz) relay with a gas detection device, which is used for fault detection and protection of power transformers. The upgrade refers to a sensor for detection of combustible gases in (Buchholz) relay, which are formed during thermal and electrical defects in active parts of power transformer. In the first part paper focuses on describing mechanisms of production of combustible gases in oil, as well as intrusion of air bubbles into transformer tank due to leaking dilatation system. The second part provides description of the simulation setup for testing performance of the gas detection device in real-life conditions. The final section describes the sensor and automation of the transfer and processing of measurement data. It also presents useful practical advantages and opportunities that the upgrade brings for various transformer sizes as well as provides an estimate of installation costs and benefits through analysis of operational reliability increase of the upgraded transformer.
LUKAČ, N., ŽLAUS, D., SEME, S., ŽALIK, B., ŠTUMBERGER, G.
METHOD FOR ESTIMATING ROOFS SOLAR POTENTIAL CALCULATED ON LIDAR DATA
KOMUNALNA ENERGETIKA / POWER ENGINERING, 23
Buildings' roofs are becoming increasingly important for photovoltaic systems installation. They can increase efficiency of electrical usage and decrease the amount of greenhouse emissions. However, not all roofs are suitable for photovoltaic systems installation. This work proposes a method for estimating roofs’ solar potential. The solar potential is calculated on LiDAR data using measurements of direct and diffuse solar irradiance from pyranometer at a given location. Multiresolutional shadowing is proposed for achieving higher accuracy in the solar potential calculation.
PRELOVŠEK, M., BIZJAK, G.
ENERGY CONSUMPTION OF PUBLIC LIGHTING (ROAD AND URBAN LIGHTING) IN SLOVENIAN MUNICIPALITIES BETWEEN 2007 AND 2011
KOMUNALNA ENERGETIKA / POWER ENGINERING, 24
The article presents an overview of energy consumption of public lighting (road and urban lighting) in slovenian municipalities between 2007 and 2011. It also explains the background of significant improvements in the quality of public lighting from the energy consumption point of view, which derived from the increasing awareness of the importance of public lighting and technological possibilities that are available on the lighting market. Three case studies of recent lighting renovations in slovenian municipalities are also analysed as to give an overview of the energy consumption reductions one can expect when renovating public lighting.
CERKOVNIK, U., ŠTUMBERGER, G.
ENERGY SELF-SUFFICIENT STREET LIGHTS (ESUS)
KOMUNALNA ENERGETIKA / POWER ENGINERING, 25
Within diploma work "The impact of street lights on energy transmission losses and possibility for realization of energy self-sufficient street lighting" were constructed two examples of energy self-sufficient street lights (ESUS). The lamp is not connected to the electricity grid and for its normal operation use energy from the wind and sun. At the top of the street pole is mounted vertical axis wind generator, which begins to operate at very low wind speeds (2-3 m/s). On the circumference of the pole is installed thin film solar panel that generate solar energy throughout the day. Possibility of installed passive infrared motion sensors and GSM monitoring and management system results as reducing electricity consumption of street lamp up to 80 percent.